Dock levelers are utilized to compensate for height differences between a dock platform and the bed of a parked vehicle to permit forklift trucks and personnel to readily move on and off the vehicle during loading and unloading operations. A typical dock leveler is mounted within a pit and has a dockboard or deck pivotally connected at its rear edge to a frame mounted within the pit for varying the height of the dock leveler in order to compensate for the height differences. An extension plate or lip is typically pivotally connected to the front edge of the deck for spanning the distance between the rear end of the vehicle bed and the outer front end of the deck and permitting forklift trucks and personnel to safely load and unload the truck without difficulty.
The deck is adapted to pivot between downwardly inclined or lowered positions, a horizontal or level position, and upwardly inclined or raised positions relative to the dock platform. When the dock leveler is not in use, the deck is substantially coplanar with the adjacent, upper surface of the dock. To permit such movement of the deck, a joint is typically formed along the adjacent edges of the deck and loading dock surface. Since dock levelers typically have a portion of the pit and the associated portions of the dock leveler which extend into the interior of the building even when the access door between the loading dock and the building interior is closed, annoying drafts may be created or conditioned air may be lost through the joint unless some type of weather sealing is utilized between the dock leveler and the wall surfaces of the pit in which the leveler is mounted.
The various other types of weather sealing which have been proposed for this purpose heretofore have certain inherent design characteristics which creates one or more of the following shortcomings: (a) an ineffective seal was created in the joint; (b) it was awkward and difficult to install or replace certain components; (c) the useful and effective life of these components was inordinately short, thereby requiring frequent shut down of the dock leveler; (d) it was of costly and complex construction and was ineffective in facilitating proper temperature control within the building interior; and (e) various components were adversely affected by changes in climatic conditions.